The first-person shooter series made its debut in 2003 as a World War II shooter, and while it was a sales and critical success for a number of years, it wasn't until 2007's Modern Warfare that it was escalated into a true blockbuster franchise, partly thanks to its innovative multiplayer that rewards players with experience and perks, ideas that other games - from fellow shooters through to racing games - have since attempted to emulate.

New Call of Duty games have since become a yearly event every November, alternating between Modern Warfare one year and Treyarch's instalment the next, with this one following on from 2010's Black Ops.

Black Ops 2 offers a number of significant changes across its three core modes - campaign, multiplayer and Zombies. In terms of setting, the campaign story jumps between the post-Cold War setting of the original and the year 2025, where cyber and robotic warfare have radically altered combat, paving the way for new weapons and equipment.

Mechanically, one of the most significant changes is the new 'Strike Force' mode, where players must order assets such as robots and jets on targets. If they lose these objectives, then the story will continue, leading to a branching narrative and a possibly different ending.

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Reviews have mixed impressions for the campaign, saying that while there are memorable set-pieces, the Strike Force elements often feel poorly implemented.

Multiplayer is what many consider the bread and butter of Call of Duty, often sweeping aside the campaign and opting to sink dozens of hours into online warfare instead.

This year offers a number of significant changes. Players are now given heightened customisation with the 'Pick Ten' system, allowing them to drop series staples like grenades or secondary weapons so they can prioritise additional skills elsewhere.

Prestiging - the ability to start your ranking over to continue playing - no longer wipes player stats clean, providing an incentive to keep moving forward and discovering new content.

Alongside the return of party modes, an improved theatre and emblem suite, critics have given high praise to this year's multiplayer, with many branding it the best yet.

First introduced in 2008 instalment World at War , Zombies mode allows players to work together to take on hordes of the undead, making the best out of limited ammo against overwhelming odds.

In Black Ops 2, this is expanded into a full campaign with an explorable world, one that can be played solo or co-operatively. Up to eight players can now work together, while two teams of four can now compete for survival in the more traditional 'Grief' mode.

Multiplayer will be expanded further with a series of map packs leading up to the next Call of Duty release next November, which can be purchased individually or through a season pass, offering a small discount.

Interestingly, one of the biggest new features is the introduction of YouTube streaming, allowing players to share their live multiplayer gameplay with anyone in the world, effectively bringing eSports to the masses. How this feature will be received by the community is uncertain, but it could see the game's popularity grow in new and unexpected areas.

The best all-round offer is from Tesco, selling the game for £25 when purchased alongside a Microsoft Points card (2100 points for £18 or 4100 points for £35), 12 months of Xbox Live Gold membership (£35) or a £25 or £35 PSN card.

GAME and Blockbuster offer a variety of trade-in offers to get the game for cheap (99p) or free, but if you're simply looking to pick it up from the shelves, then both Tesco and Asda are selling the title in-store for £39 standalone, while Morrisons offers the game for £39.99.

And for those who aren't picking it up yet, then a Wii U version - with bonus features based around the touchscreen GamePad - will launch alongside the new console on November 30.